Coro/Coro/Channel.pm

=head1 NAME

Coro::Channel - message queues

=head1 SYNOPSIS

 use Coro::Channel;

 $q1 = new Coro::Channel <maxsize>;

 $q1->put ("xxx");
 print $q1->get;

 die unless $q1->size;

=head1 DESCRIPTION

A Coro::Channel is the equivalent of a pipe: you can put things into it on
one end end read things out of it from the other hand. If the capacity of
the Channel is maxed out writers will block. Both ends of a Channel can be
read/written from as many coroutines as you want.

=over 4

=cut

package Coro::Channel;

use strict qw(vars subs);
no warnings;

use Coro ();

our $VERSION = 5.0;

=item $q = new Coro:Channel $maxsize

Create a new channel with the given maximum size (unlimited if C<maxsize>
is omitted). Giving a size of one gives you a traditional channel, i.e. a
queue that can store only a single element (which means there will be no
buffering). To buffer one element you have to specify C<2>, and so on.

=cut

sub new {
   # [\@contents, [$getwait], $maxsize, [$putwait]];
   bless [[], [], $_[1] || (1e30),[]], $_[0];
}

=item $q->put ($scalar)

Put the given scalar into the queue.

=cut

sub put {
   push @{$_[0][0]}, $_[1];
   (pop @{$_[0][1]})->ready if @{$_[0][1]};

   while (@{$_[0][0]} >= $_[0][2]) {
      push @{$_[0][3]}, $Coro::current;
      &Coro::schedule;
   }
}

=item $q->get

Return the next element from the queue, waiting if necessary.

=item $q->timed_get ($timeout)

Return the next element from the queue, waiting up to C<$timeout> seconds
if necessary. If no element arrives within the given time an empty list
will be returned.

=cut

sub get {
   while (!@{$_[0][0]}) {
      push @{$_[0][1]}, $Coro::current;
      &Coro::schedule;
   }

   (pop @{$_[0][3]})->ready if @{$_[0][3]};
   shift @{$_[0][0]}
}

sub timed_get {
   require Coro::Timer;
   my $timeout = Coro::Timer::timeout ($_[0]);

   (pop @{$_[0][3]})->ready if @{$_[0][3]};

   while (!@{$_[0][0]}) {
      push @{$_[0][1]}, $Coro::current;
      &Coro::schedule;
      return if $timeout;
   }

   shift @{$_[0][0]}
}

=item $q->size

Return the number of elements waiting to be consumed. Please note that:

  if ($q->size) {
     my $data = $q->get;
  }

is NOT a race condition but works fine.

=cut

sub size {
   scalar @{$_[0][0]}
}

1;

=back

=head1 AUTHOR

 Marc Lehmann <schmorp@schmorp.de>
 http://home.schmorp.de/

=cut

Revision:	1.69
Committed:	Fri Nov 14 02:42:26 2008 UTC (15 years, 6 months ago) by root
Branch:	MAIN
Changes since 1.68:	+1 -1 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	=head1 NAME
2
3			Coro::Channel - message queues
4
5			=head1 SYNOPSIS
6
7			use Coro::Channel;
8
9			$q1 = new Coro::Channel <maxsize>;
10
11	root	1.46	$q1->put ("xxx");
12	root	1.1	print $q1->get;
13
14			die unless $q1->size;
15
16			=head1 DESCRIPTION
17
18	root	1.8	A Coro::Channel is the equivalent of a pipe: you can put things into it on
19			one end end read things out of it from the other hand. If the capacity of
20			the Channel is maxed out writers will block. Both ends of a Channel can be
21			read/written from as many coroutines as you want.
22
23	root	1.1	=over 4
24
25			=cut
26
27			package Coro::Channel;
28
29	root	1.60	use strict qw(vars subs);
30	root	1.45	no warnings;
31
32	root	1.3	use Coro ();
33	root	1.1
34	root	1.69	our $VERSION = 5.0;
35	root	1.1
36			=item $q = new Coro:Channel $maxsize
37
38			Create a new channel with the given maximum size (unlimited if C<maxsize>
39	root	1.8	is omitted). Giving a size of one gives you a traditional channel, i.e. a
40	root	1.48	queue that can store only a single element (which means there will be no
41			buffering). To buffer one element you have to specify C<2>, and so on.
42	root	1.1
43			=cut
44
45			sub new {
46	root	1.7	# [\@contents, [$getwait], $maxsize, [$putwait]];
47	root	1.8	bless [[], [], $_[1] \|\| (1e30),[]], $_[0];
48	root	1.1	}
49
50	root	1.44	=item $q->put ($scalar)
51	root	1.1
52			Put the given scalar into the queue.
53
54			=cut
55
56			sub put {
57			push @{$_[0][0]}, $_[1];
58			(pop @{$_[0][1]})->ready if @{$_[0][1]};
59	root	1.7
60	root	1.8	while (@{$_[0][0]} >= $_[0][2]) {
61			push @{$_[0][3]}, $Coro::current;
62			&Coro::schedule;
63	root	1.7	}
64	root	1.1	}
65
66			=item $q->get
67
68			Return the next element from the queue, waiting if necessary.
69
70	root	1.47	=item $q->timed_get ($timeout)
71
72			Return the next element from the queue, waiting up to C<$timeout> seconds
73			if necessary. If no element arrives within the given time an empty list
74			will be returned.
75
76	root	1.1	=cut
77
78			sub get {
79			while (!@{$_[0][0]}) {
80	root	1.3	push @{$_[0][1]}, $Coro::current;
81			&Coro::schedule;
82	root	1.1	}
83	root	1.7
84	root	1.48	(pop @{$_[0][3]})->ready if @{$_[0][3]};
85	root	1.46	shift @{$_[0][0]}
86	root	1.1	}
87
88	root	1.47	sub timed_get {
89			require Coro::Timer;
90			my $timeout = Coro::Timer::timeout ($_[0]);
91
92			(pop @{$_[0][3]})->ready if @{$_[0][3]};
93
94			while (!@{$_[0][0]}) {
95			push @{$_[0][1]}, $Coro::current;
96			&Coro::schedule;
97			return if $timeout;
98			}
99
100			shift @{$_[0][0]}
101			}
102
103	root	1.1	=item $q->size
104
105			Return the number of elements waiting to be consumed. Please note that:
106
107			if ($q->size) {
108			my $data = $q->get;
109			}
110
111			is NOT a race condition but works fine.
112
113			=cut
114
115			sub size {
116	root	1.46	scalar @{$_[0][0]}
117	root	1.1	}
118
119			1;
120
121			=back
122
123			=head1 AUTHOR
124
125	root	1.35	Marc Lehmann <schmorp@schmorp.de>
126	root	1.33	http://home.schmorp.de/
127	root	1.1
128			=cut
129